308 maine agricultural experiment station. i916. 



Table 7. 



Showing Number of Dwarf Eggs Laid by Each Bird which 

 Produced One or More Such Eggs. 



Number of Dwarf Egos Laid by a Bird. 



Number of 

 birds. 



Per cent, 

 of birds. 



Number of 

 eggs. 



1 



178 

 15 



89.0 

 7.5 

 1.5 

 0.-5 

 0.5 

 0.5 

 0.5 



178 



2 



30 



3 



3 

 1 

 1 

 1 

 1 



9 



4 



4 





5 



8 



8 



17 



17 







Total 



200 100.0 

 r was not known, i. e., 



251 



Number of dwarf eggs laid by birds whose numbe 



47 













298 



From this table we see that of the 200 birds which produced 

 one or more dwarf eggs, 178, or 89.0 per cent, produced only 

 one, 15, or 7.5 per cent, produced two, and only 7, or 3.5 per 

 cent, more than two. The figures given by Warner and Kirk- 

 patrick (loc. cit.) for the birds in the Connecticut Station lay- 

 ing contest show an even larger percentage (94.11 per cent.) 

 of the dwarf egg producers which lay only one dwarf egg. One 

 bird laid 14 dwarf eggs and no normal eggs. Each of the other 

 four (4.71 per cent.) laid two. It is thus apparent that the 

 production of dwarf eggs is not usually an evidence of a per- 

 manent abnormality or derangement of the reproductive organs. 

 This view is strengthened by a study of the egg records for 

 the birds which produced dwarf eggs. In almost all cases these 

 birds have a normal egg record. The dwarf egg is preceded 

 and followed by normal eggs quite as though it were a normal 

 egg. Only 11 (5.5 per cent.) of the 200 birds showed evi- 

 dence of a permanent disturbance of the egg forming processes. 

 It is evident that the disturbance which causes the produc- 

 tion of a dwarf egg is usually of an accidental or at least 

 temporary nature. However, there are certain pathological 

 conditions of the oviduct which result in the formation of a 

 dwarf egg instead of a normal egg. 



The 11 cases where dwarf egg production appeared to be 

 related to a permanent disturbance of the physiology of the 

 sex organs include all of the cases where the bird produced 



